1. Technical Field
The invention relates to the field of devices for separating oxygen from a more complex gas containing oxygen to deliver the separated oxygen for use. More particularly, the invention relates to solid state electrochemical devices for separating oxygen from a more complex gas.
2. Background Art
The ceramic oxygen generation system, Integrated Manifold and Tube (IMAT), as described in U.S. Pat. No. 5,871,624, has demonstrated the capability of generating high purity oxygen at high pressure. In a typical IMAT, tubes in each row are electrically connected in parallel and each row is electrically connected in series through via wires. Using this approach, the IMATs can be operated at reasonable current and voltage levels as compared to the approach when all tubes are connected in parallel which requires larger current to generate the same amount of oxygen. Further, the via wires are inserted into the via holes on the IMAT bases. To generate oxygen with above ambient pressure, the via wires need to be sealed tightly with the ceramics.
The challenge the prior approach faces is the difficulty associated with sealing via wires and labor time and equipment/materials cost involved with via insertion. Because of the operation temperature (600-750° C.) and the conductivity requirements, only a limited number of metals such as silver (Ag), gold (Au), platinum (Pt), and their alloys can be viable candidates. From a cost standpoint, silver would generally be the best candidate. However, silver has a thermal expansion coefficient that is much larger than that of IMAT ceramics and thus makes the sealing process very challenging due to unavoidable temperature cycling in product manufacturing and application.
While the above cited references introduce and disclose a number of noteworthy advances and technological improvements within the art, none completely fulfills the specific objectives achieved by this invention.